Search Publications
The X-ray Emission of γ Cassiopeiae During the 2020-2021 Disc Eruption
Motch, C.; Smith, M. A.; Nazé, Y. +3 more
Context. γ Cas is known for its unusually hard and intense X-ray emission. This emission could trace accretion by a compact companion, wind interaction with a hot sub-dwarf companion, or magnetic interaction between the star and its Be decretion disc.
Aims: These various scenarios should lead to diverse dependences of the hard X-ray emission …
The first study of four doubly eclipsing systems
Zasche, P.; Henzl, Z.; Kára, J.
We present the discovery and the very first analysis of four stellar systems showing two periods of eclipses, that are the objects classified as doubly eclipsing systems. Some of them were proved to orbit each other thanks to their eclipse-timing-variations (ETVs) of both pairs, hence they really constitute rare quadruples with two eclipsing pairs…
Surface brightness-colour relations of dwarf stars from detached eclipsing binaries. I. Calibrating sample
Kervella, P.; Maxted, P. F. L.; Southworth, J. +19 more
Aims: Surface brightness - colour relations (SBCRs) are very useful tools for predicting the angular diameters of stars. They offer the possibility to calculate very precise spectrophotometric distances by the eclipsing binary method or the Baade-Wesselink method. Double-lined Detached Eclipsing Binary stars (SB2 DEBs) with precisely known tr…
Gaia-TESS synergy: improving the identification of transit candidates
Latham, David W.; Collins, Karen A.; Mazeh, Tsevi +5 more
Context. The TESS team periodically issues a new list of transiting exoplanet candidates based on the analysis of the accumulating light curves obtained by the satellite. The list includes the estimated epochs, periods, and durations of the potential transits. As the point spread function (PSF) of TESS is relatively wide, follow-up photometric obs…
Stellar collisions in globular clusters: Constraints on the initial mass function of the first generation of stars
Dib, Sami; Haghi, Hosein; Zonoozi, Akram Hasani +2 more
Globular clusters display an anticorrelation between the fraction of the first generation of stars (N(G1)/N(tot)) and the slope of the present-day mass function of the clusters (αpd), which is particularly significant for massive clusters. In the framework of the binary-mediated collision scenario for the formation of the second-generat…
Radio properties of the OH megamaser galaxy IIZw 096
Chen, Xi; Zhang, Bo; Wu, Hong +9 more
Based on the two-epoch European Very Long Baseline Interferometry (VLBI) Network (EVN) archive data from OH line observations of IIZw 096, we confirm that the high-resolution OH emission in this source mainly comes from two spots (OH1 and OH2) of component (comp) D1 of this merging system. We found no significant variations in the OH 1667 MHz line…
Radio observations of massive stars in the Galactic centre: The Quintuplet cluster
Alberdi, A.; Najarro, F.; Yusef-Zadeh, F. +4 more
We present high-angular-resolution radio continuum observations of the Quintuplet cluster, one of the most emblematic massive clusters in the Galactic centre. Data were acquired in two epochs and at 6 and 10 GHz with the Karl G. Jansky Very Large Array. With this work we have quadrupled the number of known radio stars in the cluster. Even though t…
Fundamental stellar parameters of benchmark stars from CHARA interferometry. III. Giant and subgiant stars
White, T. R.; Casagrande, L.; Nordlander, T. +3 more
Context. Large spectroscopic surveys of the Milky Way must be calibrated against a sample of benchmark stars to ensure the reliable determination of atmospheric parameters.
Aims: Here, we present new fundamental stellar parameters of seven giant and subgiant stars that will serve as benchmark stars for large surveys. The aim is to reach a pre…
Radio detection of chemically peculiar stars with LOFAR
White, Glenn J.; Haverkorn, Marijke; Vedantham, Harish +5 more
Context. Chemically peculiar stars are upper main sequence stars that show anomalies in their optical spectra. These anomalies suggest peculiar chemical abundances of certain elements. Some chemically peculiar stars possess strong magnetic fields. Electrons originating from the ionising stellar wind travel in the magnetosphere of the star and beco…
Peculiar hydrogen-deficient carbon stars: strontium-rich stars and the s-process
Clayton, Geoffrey C.; Tisserand, Patrick; Crawford, Courtney L. +1 more
Context. R Coronae Borealis (RCB) variables and their non-variable counterparts, the dustless Hydrogen-deficient Carbon (dLHdC) stars have been known to exhibit enhanced s-processed material on their surfaces, especially Sr, Y, and Ba. No comprehensive work has been done to explore the s-process in these types of stars, however one particular RCB …